Great strides have been made in the treatment of Antl-Neutrophil Cytoplasmic Autoantibody (ANCA) - associated glomerulonephritis and small vessel vasculitis (ANCA disease). However major challenges remain In the form of mortality, and Irreversible organ damage, elevated rates of disease relapse and significant risks of severe adverse effects from current conventional therapy. New concepts have recently emerged from In vitro and animal studies that pertain to the mechanisms by which ANCA are induced, and those detailing their role in the vascular Injury leading to glomerulonephritis and vasculitis. Our group has introduced strong evidence in support of (1) the important role of complement activation in the pathogenesis of ANCA disease in the mouse model, (2) epigenetic dysregulation leading to aberrant expression of the leukocyte myeloperoxidase and PRS genes as a possible mechanism of disease relapse, and (3) protein complementarity as a trigger to autoimmunity to proteinase 3 (PR3) and plasminogen. The newly discovered antlplasmlnogen antibodies inhibit fibrin degradation and are hypothesized to contribute to the increased risk of thromboembolic event seen In patients with ANCA disease. The ultimate test of relevance of these new concepts lies in their applicability to human disease. The overall goal of this project is to test the impact of our advances on the treatment of ANCA disease through novel approaches to therapy. We will do so through two proof of concept, interventional, open label, randomized and controlled clinical trials. Specific Aim 1 will test the novel concept of inhibiting complement activation in patients with active de novo or relapsing disease using the monoclonal antibody to complement factor C5, Ecullzumab (Sollris) as an adjunct to conventional induction therapy. Specific Aim 2 will test the concept of modulating autoantigen gene expression on the course of disease using all-trans retinoic acid (tretinoin) as an adjunct to conventional maintenance therapy in patients with mild or moderate disease activity. In a screening cohort study, Specific Aim 3 will test the impact of the anti-plasminogen autoantibodies on the detection and risk of thromboembolic events, a well recognized complication of ANCA disease.